The present invention relates to a hand-operated implement for discharging pasty substances, such as sealing compounds, with a cylinder for receiving the substance, particularly for receiving a cartridge containing the substances, a plunger axially displaceable in the reception cylinder, a device for axially displacing the plunger and a manually operable device for discharging a desired quantity.
The hitherto known implements of this type include those in which a mechanical device, generally equipped with a rack is provided for the axial displacement of the plunger. In the case of such implements, the plunger can only be axially displaced in stepwise manner, so that such implements have only proved satisfactory in those cases where uniform material discharge is not required, such as in the case of pressed lubricating grease. However, if such implements are used for discharging pasty sealing compounds or the like for the purpose of filling visible gaps, such as those which unavoidably occur when fitting baths, their non-uniform material discharge leads to labourintensive aftertreatment of the joined areas.
Therefore, implements of the aforementioned type have already been developed, in which the axial displacement of the plunger takes place by compressed air supplied via a flexible hose. These hand-operated implements operating with compressed air require a relatively high apparatus expenditure and can also not be used in all cases, namely if there is no compressor or no power supply for operating the compressor. In addition, the pressure hose leading thereto is often also disadvantageous in connection therewith.
In addition, implements of the aforementioned type have been developed, in which the axial displaceability of the plunger is brought about by a compressed gas supplied thereto from a small compressed gas cartridge housed in the implement. However, in the case of such implements, sealing problems occur, which are particularly serious in view of the limited cartridge volume. It is also disadvantageous therewith that it is not readily possible to determine the degree of filling of the compressed gas cartridge, so that spare cartridges have to be kept. In addition, such implements do not permit precise working, because their discharging means have a rotary slide valve, which cannot be operated in a sensitive manner.